I find it most interesting that they rely on irc internally. They work on one of the world's largest online communications platforms -- surely they could solve their problem in a way that gives it to their millions of users too?
IRC's ability to quickly create temporary groups, temporary membership (essentially muting discussion by leaving, or peeking by joining), bot frameworks, and multiple clients are potential reasons why IRC might be preferable for the sort of things it is used for, I guess.
There is no need to re-invent IRC.
A real-time low-friction shared chat service would actually be a hugely compelling thing inside Facebook.
How so?
(just curious, I used it before in a corporate environment, it was fine for us)
It's almost like right now we're in the days of pine and mailman. What we could have is GMail.
We were all Unix geeks, so perhaps that's why it worked well for us.